Electric plug and socket



w. J. PRlTcHET-r v ELECTRIC PLUG AND SOCKET Nov. 26, 1929.

Filed Sept. 7, 1927 Patented Nov. 26, 1929 WILLIAM JACOB PRITCIIETT, FSYDNEY, AUSTRALIA ELECTRIC PLUG AND SOCKET- Application filed September7, 1927, Serial No.

This invention relates to plugs and sockets such as are used forconnecting electrical apparatus to the source of supply and the objectof the invention is to provide a simple and eective arrangement ot' plugand socket whereby connection between the circuit and the apparatus maybe completed by inserting the plug and may be broken quickly and withoutarcing under full load by simply withdrawing the plug from the socketthus rendering a switch in the circuit unnecessary.

The plug is provided with as many longitudinally slidable pins as may benecessary for the particular apparatus, which pins are normally heldback in the plug by springs .or the like. Each pin is provided with agroove near the forward end and each pin has means whereby electricalcontact is established between it and terminals on the plug to which theleads are connected. The socket consists of an insulating casing havingin it a number of individual sockets corresponding to the number oi'pins in the plug.

Each is provided near the open end with a vfspring controlled pin whichprojects slightly into the central passage.

The invention may be clearly understood by referring to the accompanyingdrawings in which Figure 1 is a sectional elevation of the complete plugand socket when the circuit is fully established,

Figure 2 is a sectional elevation or" the plug and socket when thecircuit is about to be broken,

Figure 3 is a plan of the socket,

Figure 4 is a sectional eleva-tion of the socket,

Figure 5 is a plan of the. cap of the plug, and

Figure 6 is a plan of the plug with the cap removed.

The plug consists of a base 7 and a cap 8 formed of any suitable andwell known insulating material. The base is provided with plates 9 whichare inserted or attached to it in any well known manner and through eachplate apin 10 is adapted to slide, the pin being formed with a flange 11against which the spring 12 bears, and being provided with a groove 13and an insulating sleeve 14 at the 218,065, and' in Australia November19, 1926.

tip. The plates 9 are provided with terminals 15 to which the leads 16lare attached, being brought in through the notches 17 and kept wellseparated by the partition 19.

The socket consists of a casing 20 also formed or'l any suitableinsulating material in which are retained by any well known means theindividual sockets 21 arranged to register with the pins 10. Each socketconsists oi conducting material and is provided with an inwardlyprojecting pin 22, which is pressed inwards by the spring 23, and aclamping device 24 for the reception oi' the incoming wire 25. Aninsulating partition 26 is provided and also means 27 for attaching thecover 28 to the casing 20.

The plug is inserted in the usual manner so that the pins 10 enter thesockets 21 and it is pushed in until the. pins take up the positionshown in Figure 1. The insulated tips 14 prevent the passage of anycurrent when the tips are just inserted and it is necessary to push theplug in untill the resistances of the small pins 22 are overcome whenthe plug suddenly slides into position and the pins 22 enter the grooves13 thus ensuring that only a complete and good contact is made. Amplecontact is established between the pin 10 and the sockets 21 bytheaction of the springs 23 and pins 22 which press the pins 10 against thesockets 21, the insulating sleeves 14 being of slightly less diameterthan the pins. Current is carried from the pins 10 to the plates 9 bothby direct contact and by the springs 12 which bear tightly against theflanges 11 and the plates 9.

On withdrawing the plug to break the circuit, the springs 12 arecompressed until the parts are in the position shown in Figure 2 and theresistance of the pins 22 in the grooves 13 is finally overcome. Thepins 10 are then suddenly released to ily back under the influence otthe springs 12 to make a sudden clean break of the circuit between thepins 10 and the socket 11.

rlhe depth of the sockets 21 may be increased so that the pins 22 willenter and leave again the grooves 13 as the plug is inserted but thepins will arrest momentarily the Withdrawal motion until the springs 12have been compressed.

The insulation of the socket casing is carried Well over the contacts sothat risk of shock or short cireuiting is eliminated and the length ofthe pins l0 and insulating sleeves 14 may be so proportioned that Whenthe pinsV are inade live there Will not be sufiioient room between theplug and the socket for the operator to come in contact with the pinsl0, and a hand knob 29 may be provided so that the plug may be easilygripped.

Additional pins and sockets may be provided to suit the circuit or typeof apparatus which is being used and an eXtra pin may be provided forcontrol of the circuit to a pilot lamp or the like, if any be used withthe apparatus connected to the plug.

I claim :v-

Anelectrical plug and socket fitting coinprisingv a base portion, aplurality of pins slidably mounted on said base portion, each of saidpins being provided With a groove, spring means normally holding saidpins in fixed position With respect to said base porL tion, a pluralityof socketsmeans on said sockets for yieldably engaging said grooves, andinsulating means surrounding the end of each pin adjacent said groove.

In testimony whereof I have aiixed by signature.

WILLIAM JACOB PRI'ICHETT.

